Die-cuts of various materials are used to provide mechanical assembly of two (2) parts as in adhesive tapes, sealing of parts as in gaskets with or without adhesives, and other functions. In these instances, the die-cuts are typically placed between two (2) parts to achieve specific purposes, e.g. the assembly or sealing of the parts. Die-cuts of appropriate materials are also used for functions such as masking as in tapes with adhesive on one side of a film, shielding from RFI/EMI (radio frequency interference/electro magnetic interference), and for other purposes. Adhesive tapes with adhesive only on one (1) side of a film are typically used for masking applications.
Die-cuts are manufactured by cutting chosen materials into desired geometric designs. This is accomplished by diverse techniques depending on the material. Typically, for organic materials such as films, adhesive tapes, pads, foams and others, mechanical stamping dies are used. Computer controlled cutting tools such as knife and laser and other methods are employed to manufacture die-cuts as well.
For typical mechanical assembly purposes, adhesive die-cuts are used to bond two mechanical parts together, such as portions of a cell phone. Adhesive die-cuts are typically pressure sensitive adhesives provided in the form of tapes. Pressure sensitive adhesive tape consists of only the adhesive material and is typically available in rolls. Double coated tape consists of adhesive coated on both top and bottom sides of a film. The film may be made of polyester and other organic and inorganic materials.
The pressure sensitive adhesive products described above are typically carried on and/or covered by liners for ease of handling, processing and storage. Typically these liners are surface treated papers or organic films such as polyester. More than one (1) liner may be employed for easier handling, processing and storage. For example, a bottom liner may be a carrier liner on which the adhesive is placed or carried and a top liner may cover the top of the adhesive. Both the top and bottom liners may be peel off liners.
Adhesive films are typically not tacky at normal room temperature and are also provided on liners. Unlike pressure sensitive adhesive products, such adhesive films are typically employed in the mechanical assembly of parts by applying both heat and pressure.
Die-cuts consisting of more than one (1) laminate material are used to achieve specific application purposes. Many diverse materials are used in creating the laminate structure.
To mechanically bond two parts together, die-cuts of the above-mentioned adhesive products are cut to desired designs that typically mimic the contact surface geometry of the mechanical parts.
The current art of manufacturing die-cuts in high volume is to use mechanical dies to stamp or cut the target materials provided in sheets or rolls. Typically a stamping tool has a flat base containing the cutting edges arranged in the desired geometric design of the die-cut. The stamping tool travels in vertical motion to stamp, punch or cut the design on the target material. The technique of cutting the target materials with controlled cutting depth is called kiss-cutting. Typically, the target material with one (1) or two (2) liners is kiss-cut leaving the liner that is located at the furthest point from the cutting tool intact. For higher speeds of die-cutting, rotary dies may be used with rolls of materials to manufacture die-cuts.
In its simplest form, a roll of single coated adhesive tape with a protective liner is repeatedly kiss-cut using a cutting die mounted on a flat press machine. Upstream of the flat press machine, the roll of tape unwinds and the tape travels across the platform of the flat press machine. The cutting die moves in a perpendicular direction to the tape and punches through the single coated tape, but not the bottom liner to create kiss-cut die-cuts. Downstream, the kiss-cut tape is rewound into a roll. Afterward, any unwanted area of the die-cut tape is either removed manually by hand or by using a continuous roll of another tape to selectively remove the unwanted area. In a more sophisticated process, the removal of the unwanted area using a roll of another tape is incorporated into the die-cutting process in a single machine or a single process flow line.
In this known process of manufacturing die-cuts, the unwanted area of the die-cut, including the relatively expensive adhesive covering such area, is discarded as waste. It is not unusual that the unwanted areas of the die-cut comprise a majority of the overall area of the die-cut with the desired areas of the die-cut comprising only a small percentage of the area. Thus, much of the adhesive portions of the die-cut end up being cut out and discarded as waste. This increases the materials cost in manufacturing the die-cuts, leading to a more expensive purchase price for the die-cuts.
In addition, the current art of removing the unwanted area may slow down the die-cut manufacturing process when done manually by hand. For an automatic continuous removal process, the extra process steps of removing unwanted area without affecting the pattern and integrity of the wanted area adds process steps, complications and the cost of employing additional tapes and liners. The current roll to roll process method increases the complexity of the die-cutting process especially when there are multiple layers with different layers needing different geometric die-cut designs. Because the removed unwanted materials are discarded, the cost of the final die-cuts includes all material costs, both wanted and unwanted, as well as the costs of other tapes and liners used to remove the unwanted areas.